Typically a set of folding stairs is provided in the ceiling to allow walk-up access to the attic. A problem associated with this arrangement is the lack of insulation provided between the attic and the room below when the stairs are in their folded position. Typically, this opening is left uninsulated since the folding stairs occupy the space where insulation would normally reside. This results in a loss of heat and/or cooling from the room below the attic opening into the attic.
Devices have been developed which attempt to cover the pull-down stairs in an attic, however these devices have limitations which affect their use. One such device is shown in U.S. Pat. No 4,281,743 to Fuller (hereinafter Fuller). The device of Fuller comprises multiple pieces having overlapping tongue-and-groove sections. The Fuller device thus requires assembly of its interlocked structure. The use of multiple pieces can reduce the overall thermal efficiency, as well as affect the strength and rigidity of the cover. The Fuller device may also come apart, and may requires use of a binding strap to keep the unit whole, as discussed on column 7, lines 17-28.
Another attempt to solve the problem of thermal loss through an attic access way is shown in U.S. Pat. No. 4,299,059 to Smith (hereinafter Smith). Smith discloses an insulated, fire resistant attic door. In Smith, the pull-down door that supports at least a part of the folding stairway includes a layer of insulative material. The Smith device cannot be used in previously installed pull-down stairways, and would thus be labor intensive to install as well as incur significant cost to retrofit existing pull-down stairways.
U.S. Pat. No. 4,550,534 to Mariano et al. (hereinafter Mariano) is another attempt to solve the problem of thermal loss through an attic access way. The device of Mariano includes a hinged cover, a latching mechanism and a leaf spring. The Mariano device thus requires mechanical installation, and has several moving parts which can wear out or otherwise fail.
U.S. Pat. No. 4,563,845 to Stipe (hereinafter Stipe) comprises a cover which is attached to the ceiling side of the door of the pull-down stairway. The Stipe device thus extends into the room having the attic opening, providing an extended portion of the ceiling, and making the presence of the attic access way much more noticeable.
Devices available from Atticcap (www.atticcap.com) and from Thermalid (www.thermalid.com) are only useful in attics having a finished floor. These devices have narrow base structures which rely on the attic having a finished floor in order to provide the thermal barrier. For attics having unfinished floors, these devices do not provide a continuous thermal barrier.
Additional devices such as the Attic Tent available from Insulsure (www.insulsure.com) comprise a tent-like structure. A base portion is mechanically attached to the attic floor, and a hood is attached to the base portion by a zipper. This makes the device difficult to close and open since the hood portion must be unzippered to access the attic and then zippered to close the attic opening. Zippers can jam and break, rendering the attic space unusable. There may additionally be thermal loss through the zipper structure.
Birdzone (www.birdzone.com) produces a folding attic stair insulator comprising a backbone of PVC piping to with fabric is attached to provide the cover. The Birdzone device requires assembly and installation. Since the device is not rigid in structure, the fabric could easily become damaged during removal and installation of the insulator, thus reducing the thermal insulation provided by the device.
In view of the foregoing it would be desirable to provide a rigid insulating cover which fits over an access opening to an attic or other space and provides a thermal barrier in order to prevent or minimize the loss of heat or cooling air from a room into the attic. It would be further desirable to provide such a cover which is also easy to install, easily moved when necessary, and which is useful for both finished attic floors and unfinished attic floors and which has a low profile.